Inhalation device

ABSTRACT

The present invention relates to an inhalation device for use with an inhaler ( 5 ) comprising a dispersion chamber ( 18 ) for fluid communication with the inhaler ( 5 ) and a suction chamber ( 19 ) in fluid communication with the dispersion chamber ( 18 ). The suction chamber ( 19 ) is constructed to enable the internal volume of the suction chamber ( 19 ) to be increased during use thereby producing a negative pressure in the dispersion chamber ( 18 ). In this way, the substance to be inhaled can be drawn from the inhaler into the dispersion chamber ( 18 ) for subsequent inhalation.

[0001] The present invention relates to an inhalation device forinhalation of a pharmaceutically active substance prepared in adispersed state.

[0002] Inhalable pharmaceutically active substances are generally usedfor the treatment of diseases in the bronchial and pulmonary area, suchas asthma and chronic bronchitis. Various types of inhalation devices orapparatus are used for this purpose.

[0003] The breath-actuated inhaler is known and used widely, typicallycontaining multiple doses of a medicament containing an activesubstance. The breath-actuated inhaler usually contains a dry powderedmedicament and comprises a manoeuvring element which loads a single doseof the medicament into a dosing unit which can then be inhaled by theuser. Inhalers of this kind are described in EP-0,069,715, EP-0,237,507and WO98/41256, for example.

[0004] The inhaler described in the above-mentioned patents is known asthe Turbuhaler® inhaler and is particularly advantageous for deliveringa dry powdered medicament. The Turbuhaler® inhaler depends on thecreation of an airflow through the inhaler which will normally becreated by the user inhaling. The airflow will cause the dry powderedmedicament to be moved from a release position in the dosing unit intothe airflow where it is dispersed and delivered to the mouth of theuser. It is important that there is a break down of aggregated particlesduring inhalation because aggregates always occur in powders having fineparticles, especially finely divided particles of the type generallyused for inhalation.

[0005] The Turbuhaler® inhaler is a manually actuated inhaler intendedto be easily carried by the user and actuated when necessary. However,the user must be able to achieve the necessary inhalation flow to movethe dry powdered medicament from the release position in the dosing unitinto the airflow. Some patients such as small children and elderlypeople with diseases in the bronchial area are unable to use thebreath-actuated inhaler because they simply do not have sufficient lungcapacity to create the necessary inhalation flow. The airflow needed isapproximately 30 to 60 l/min and patients not having the ability toachieve that airflow must use inhalers which utilise pressurised gas.e.g., freon (CFC) to deliver the medicament. However, pressurised gasinhalers have many disadvantages such as unwanted side effects both forthe patient and the environment.

[0006] In order to facilitate the use of breath-actuated inhalers,inhalation devices have been developed which make use of a dispersionchamber into which the captive substance is dispersed and then simplyinhaled by the patient. Such inhalation devices are described inEP-0,548,152 and WO 97/11732 where the breath-actuated inhaler isinserted into the inhalation device. This type of inhalation device(generally known as a “spacer”) is primed for use either by the patient,the nurse or the parent and the patient need only inhale the activesubstance which has been dispersed in the dispersion chamber. In WO97/11732, the inhalation device is primed for use by creating a negativepressure in the dispersion chamber which draws out the active substancefrom the dosing unit within the inhaler. The inhalation device describedin WO 97/11732 was designed for use with a breath-actuated inhaler suchas the Turbuhaler® inhaler and is operated by lifting the dispersionchamber away from the base and then rotating the dispersion chamber. Atthe end of the rotational movement, a piston is released which createsthe negative pressure in the dispersion chamber. When the dispersionchamber is rotated, the breath-actuated inhaler is held in theinhalation device in such a way that the manoeuvring element in the formof a rotatable gripping part is also rotated. The rotation of thegripping part releases the active substance into the dosing unit.Accordingly, when the piston is released the airflow arising due to thenegative pressure in the dispersion chamber will draw out the activesubstance from the inhaler into the dispersion chamber. The patient isthen able to inhale the dispersed substance through a mouthpiece or facemask without having to produce a vigorous intake of breath to create anairflow.

[0007] Whilst the spacer described above works effectively, afterrepeated use the active substance will build up on the interior surfacesof the device which could be dislodged and affect the dose accuracy.Indeed, the build-up of active substance has to be addressed becauseafter a given period, contact with moisture within the device will leadto degradation of the active substance which could be potentiallyharmful. There is also a demand for an inhalation device which is morecompact, more robust and attractive to the patient (who often will haveto carry the spacer and use the spacer in a variety of differentsituations).

[0008] A further requirement of the spacer is that it is also able towork with an inhaler of the kind described in WO 98/41256. This versionof the Turbuhaler® inhaler is similar to the earlier Turbuhaler® inhalerdescribed in EP 0,069,715 but further comprises a rotating mouthpiecedesigned to actuate a scraping element which passes over the interiorsurfaces of the inhaler such that the inhaler can be cleaned prior toeach use. With this in mind, there is also a demand for an inhalationdevice which incorporates a means for rotating the mouthpiece as well asthe gripping part of the inhaler.

[0009] According to the present invention there is provided aninhalation device for use with an inhaler comprising a dispersionchamber constructed for fluid communication with the inhaler, a suctionchamber in fluid communication with the dispersion chamber, the suctionchamber being constructed to enable the internal volume of said suctionchamber to be increased during use which produces a negative pressure insaid dispersion chamber thereby drawing a substance to be inhaled fromthe inhaler into the dispersion chamber for subsequent inhalationwherein, in use, the dispersion chamber is mounted telescopically aroundthe inhaler.

[0010] Preferably, a piston is moveable within the suction chamber.

[0011] Preferably, the piston has an annular construction.

[0012] Preferably, the piston carries an annular seal member.

[0013] Preferably, the annular seal member comprises inner and outercoaxial annular seals.

[0014] Preferably, the inhalation device comprises a filter between thedispersion chamber and suction chamber to prevent the dispersedsubstance from entering the suction chamber.

[0015] Preferably, the dispersion chamber is mounted telescopicallywithin the suction chamber.

[0016] Preferably, the piston is releasably connected adjacent to andmoveable with the dispersion chamber which is moveable between aretracted position, where it surrounds the inhaler, to an extendedposition, where it sits substantially above the inhaler.

[0017] Preferably, there is provided a releasing mechanism for releasingthe piston from the dispersion chamber and a biasing means for biasingthe piston away from the dispersion chamber when in the extendedposition and the device is primed for use.

[0018] Preferably, when the piston is released the movement of thepiston within the suction chamber creates a negative pressure in thedispersion chamber thereby drawing air through the inhaler.

[0019] Preferably, the inhalation device comprises a base and a body andis primed for use by lifting the body away from the base and thenrotating the base with respect to the body.

[0020] Preferably, the dispersion chamber is located in the body and theinhaler is held in the base.

[0021] Preferably, the inhaler has a mouthpiece, a body portion and arotatable gripping part.

[0022] Preferably, the inhaler is located within the inhalation device,the rotatable gripping part is held in the base of the inhalation deviceso that the rotation of the base causes rotation of the rotatablegripping part.

[0023] Preferably, the rotation of the gripping part of the inhalercauses the substance to move into a release position within the bodyportion of the inhaler.

[0024] Preferably, the inhaler mouthpiece is rotatable having a scrapingmeans acting on its interior surfaces which cleans the inhaler prior toeach use.

[0025] Preferably, the inhalation device further comprises a connectingmeans which links the rotational movement of the gripping part of theinhaler to the rotational movement of the mouthpiece of the inhaler suchthat rotation of the base in one direction results in the cleaning ofthe interior surfaces of the inhaler

[0026] Preferably, the inhalation device further comprises a clampingmeans which holds the body portion of the inhaler whilst allowing thegripping part to rotate with the base.

[0027] Preferably, the body of the inhalation device further comprises ameans for drying the air contained within the device and the substanceto be inhaled.

[0028] Preferably, the body of the inhalation device further comprises anumber of separable elements which can be replaced after a predeterminednumber of uses.

[0029] Preferably, the inhalation device comprises a stop element whichis configured to ensure that only certain inhalers can be inserted intothe device.

[0030] Preferably, there is further provided a cover which at leastpartially encases the inhalation device when not in use.

[0031] Preferably, the cover seals and encases the body of the deviceand connects with the base of the device.

[0032] Preferably, the cover and base include parts of an artwork whichis only made complete when the user has replaced the cover on the basethereby ensuring that the contents of the inhalation device are sealedwithin.

[0033] Preferably, the inhalation device comprises an audible alarmwhich is activated after a given period of time should the cover not bereplaced.

[0034] A preferred embodiment of the present invention will now bedescribed in detail, by way of example only, with reference to theaccompanying drawings, of which:

[0035]FIG. 1 is an exploded view of all the components of an inhalationdevice in accordance with the present invention and an inhaler;

[0036]FIG. 2 is a perspective view of the cover for the inhalationdevice;

[0037]FIG. 3 is a side view of the cover in FIG. 2;

[0038]FIG. 4 is a sectional view through the cover in FIG. 3;

[0039]FIG. 5 is a view from below in direction A in FIG. 2 depicting theinterior of cover;

[0040]FIG. 6 is a perspective view of the base of the inhalation device;

[0041]FIG. 7 is a side view of the base in FIG. 6;

[0042]FIG. 8 is a view in direction A of the interior of the base inFIG. 6;

[0043]FIG. 9 is a sectional view through the base in FIG. 7;

[0044]FIG. 10 shows detail of the threaded socket for an inhaler in FIG.9;

[0045]FIG. 11 is a side view of the inhalation device in FIG. 1 with thecover removed and the body in the retracted position;

[0046]FIG. 12 is a sectional view in direction X-X through theinhalation device in FIG. 11;

[0047]FIG. 13 is a sectional view in direction Y-Y through theinhalation device in FIG. 12;

[0048]FIGS. 14, 15 and 16 correspond to the views in FIGS. 11, 12 and 13when the body of the inhalation device is in the extended position;

[0049]FIGS. 17, 18 and 19 correspond to the views in FIGS. 14, 15 and 16with the base rotated by a predetermined angle just prior to release ofthe piston;

[0050]FIGS. 20, 21 and 22 correspond to the views in FIGS. 17, 18 and 19after the piston has been released;

[0051]FIG. 23 is a perspective view of the gripping collar;

[0052]FIG. 24 is a sectional view through the gripping collar in FIG.23;

[0053]FIG. 25 is a perspective view of the mouthpiece drive support;

[0054]FIG. 26 is a sectional view through the mouthpiece drive supportin FIG. 25;

[0055]FIG. 27 is a perspective view of the inner sleeve;

[0056]FIG. 28 is a sectional view through the inner sleeve in FIG. 27;

[0057]FIG. 29 is a perspective view of the mouthpiece seal support;

[0058]FIG. 30 is a sectional view through the mouthpiece seal support inFIG. 29;

[0059]FIG. 31 is a perspective view of the mouthpiece drive;

[0060]FIG. 32 is a sectional view through the mouthpiece drive in FIG.31;

[0061]FIG. 33 is a view in direction A of the mouthpiece drive in FIG.32;

[0062]FIG. 34 is a perspective view of the disposable inner sleeve;

[0063]FIG. 35 is a sectional view through the disposable inner sleeve inFIG. 34;

[0064]FIG. 36 is a perspective view of the inner piston sleeve;

[0065]FIG. 37 is a sectional view through the inner piston sleeve inFIG. 36;

[0066]FIG. 38 is a perspective view of the latch support ring;

[0067]FIG. 39 is a sectional view through the latch support ring in FIG.38;

[0068]FIG. 40 is a perspective view of the piston;

[0069]FIG. 41 is a sectional view through the piston in FIG. 40;

[0070]FIG. 42 is a view from above of the piston seal;

[0071]FIG. 43 is a sectional view through the piston seal in FIG. 42;

[0072]FIG. 44 shows detail of the piston seal in FIG. 43;

[0073]FIG. 45 is a perspective view of the outer sleeve;

[0074]FIG. 46 is a view in direction A of the outer sleeve in FIG. 45;

[0075]FIGS. 47, 48 and 49 show different views of the piston clamp ring;and

[0076]FIG. 50 is a sectional view through the external sleeve.

[0077] In the exploded view in FIG. 1 and with reference to FIG. 11, theinhalation device can be seen to comprise a base 1, a body 2, a cover 3and an optional face mask 4. An inhaler 5 suitable for use with theinhalation device can be seen beneath the base 1.

[0078]FIGS. 2 and 3 show details of the cover 3 which comprises a domedclosed end 6 and a threaded open end 7. The closed end 6 is contoured tofit over the body 2 of the inhalation device (see FIG. 11). Inparticular, the cover 3 includes a head 6 a which is contoured to fitover the mouthpiece 17 on the body 2. The cover 3 also includes aplurality of shallow recesses 8 which enable a user to grip the cover 3to remove it from the base 1. The external configuration of the cover 3could clearly be modified to suit different end requirements. However,the internal configuration of the cover 3 should preferably fit closelyaround the body 2 to avoid the presence of a large body of humid airsitting in that area of the inhalation device which would have to beaddressed by increasing the volume of the desiccant disc 48 (describedlater).

[0079]FIGS. 4 and 5 are further views of the cover 3 being a sectionalview and a view from below in direction A in FIG. 2 respectively.

[0080]FIGS. 6, 7 and 8 depict the base 1 which comprises a skirt 9 witha first open end 10 which is threaded for cooperation with the threadedend 7 of the cover 3 and a second open end 11 through which the inhaler5 (shown in FIG. 1) can be inserted into the inhalation device. A floor12 is located at the second open end 11 with a hole 13 therethrough forinsertion of the inhaler 5. The skirt 9 has a plurality of shallowrecesses 14 which enable a user to grip the base 1.

[0081]FIG. 9 shows further detail of base 1 in cross-section. Inparticular, it can be seen that the hole 13 is formed with a threadedinternal surface 15 which is intended to cooperate with the inhaler 5just above the rotatable gripping part 5 c depicted in FIG. 1.

[0082]FIG. 11, 12 and 13 depict the inhalation device when assembledwith the cover 3 removed. The body 2 is in the retracted position andthe inhaler 5 has been inserted into the inhalation device. FIGS. 12 and13 are sectional views in directions X-X and Y-Y through the inhalationdevice.

[0083] It is clear that the inhaler 5 sits centrally within theinhalation device which makes the design extremely compact. The body 2comprises numerous elements which can be seen in the exploded view inFIG. 1. The body 2 includes an external wall 16 with a mouthpiece 17which will sit inside the head 6 a when the cover 6 is in position.There is a dispersion chamber 18 and a suction chamber 19 which are influid communication with each other. An annular piston 58 is moveable inthe volume which comprises the suction chamber 19 and it is clear fromFIGS. 12 and 21 that the piston 58 actually forms the lower moveablewall of the suction chamber 19. The dispersion chamber 18 is mountedtelescopically within the suction chamber 19. Furthermore, thedispersion chamber 18 is mounted telescopically around the inhaler 5.

[0084] Preferably, the volume of dispersion chamber 18 is such that anyparticles dispersed in the volume will rise only to the top of thechamber and not into the volume beyond. In this way, the particlesshould not enter the upper volume of the body 2 and fall into theflanged rim of inner sleeve 42 (described in detail later). Theinhalation device preferably includes a filter which sits in the areabetween the dispersion chamber 18 and suction chamber 19 to avoidparticles affecting performance of the elements in the suction chamber19. In the embodiment depicted, the filter 71 sits above the holes 43and is in the form of a ring. A large number of filter materials couldbe used to form the ring. In order to avoid the particles entering thesuction chamber 19, the volume of the dispersion chamber 18 must besignificantly larger than the suction volume of the annular piston 58.For example, the suction volume of the piston 58 will typically be 70 mlwhereas the volume of dispersion chamber 18 will typically be 200 ml.However, the volume of the dispersion chamber 18 should be minimised, ifpossible, in order to make the inhalation device as compact as thedesign will allow. Furthermore, if the volume of the dispersion chamber18 is minimised, the inhalation device will be easier to use, requiringa smaller inhalation capacity.

[0085] In order to reduce the occurrence of particles sticking to theinterior surfaces of the dispersion chamber 18, the material used forthis element and other elements which make contact with the particlesshould comprise a polymeric material containing carbon black.

[0086] The inhaler 5 is inserted into the inhalation device from belowthrough the base 1 whilst the body 2 is in the retracted positiondepicted in FIGS. 11, 12 and 13. The gripping part 5 c is held in thebase 1 by way of the threaded internal surface 15 which cooperates withcorresponding threads 21 which are located just above the gripping part5 c on the inhaler 5.

[0087] The body portion 5 b of the inhaler is held with respect to aninner sleeve 22 by a gripping collar 23. The gripping collar 23 canslide inside a mouthpiece drive support 24 which is fixed with respectto the base 1.

[0088] Reference should now be made to FIGS. 23, 24, 25 and 26 fordetails of the features of the gripping collar 23 and mouthpiece drivesupport 24.

[0089] The gripping collar 23 has two ears 25 which, when in positionwithin the mouthpiece drive support 24 (with the inhaler 5 inserted intothe device) will seat against the inner surface of the inner sleeve 22.The gripping collar 23 is forced down inside the legs 26 of themouthpiece drive support 24 towards the annular base 27 by a spring 28.It is clear from FIG. 12 that the spring 28 will sit against the ears 25of the gripping collar 23. The body portion 5 b of the inhaler 5 isslightly tapered towards the mouthpiece 5 a and accordingly, the spring28 will push the gripping collar 23 into firm contact with the bodyportion 5 b.

[0090] The spring 28 is slightly compressed between the gripping collar23 and a mouthpiece seal support 29. The action of forcing the grippingcollar 23 down the body portion 5 b ensures that the body portion 5 band inner sleeve 22 cannot move with respect to each other.

[0091] For details of the inner sleeve 22 and mouthpiece seal support 29reference should now be made to FIGS. 27, 28, 29 and 30.

[0092] The mouthpiece seal support 29 is substantially cylindrical andis fixed with respect to the inner sleeve 22 which is also substantiallycylindrical. The inner sleeve 22 has three slots 30 and three holes 31which allow air to flow through the inhalation device and into theinhaler 5 when the body 2 has been lifted to the extended position. Theinner sleeve 22 is not secured in the base 1 and remains stationary ifthe base 1 is rotated. The inner sleeve 22 will allow the mouthpiecedrive support 24 to rotate within it and, therefore, the gripping part 5c and mouthpiece 5 a of the inhaler 5 will rotate with the base 1 whilstthe inner sleeve 22 remains stationary and holds the body portion 5 b ofthe inhaler 5 by way of the gripping collar 23.

[0093] The mouthpiece seal support 29 has two slots 32 and an inner rim33. The slots 32 allow movement of the ears 25 on the gripping collar 23when the inhaler 5 is inserted into the inhalation device. The inner rim33 acts as a bearing surface for the spring 28 which sits between theinner rim 33 and the ears 25 on the gripping collar 23.

[0094] The rotational movement of the gripping part 5 c of the inhaler 5is linked to the rotational movement of the mouthpiece 5 a of theinhaler 5 by a mouthpiece drive 34. The mouthpiece drive 34 is connectedto the mouthpiece drive support 24.

[0095] Reference should now be made to FIGS. 31, 32 and 33 which showdetails of the mouthpiece drive 34. The mouthpiece drive support 24 hastwo legs 26 which slot into two recesses 35 formed in the mouthpiecedrive 34. The mouthpiece drive 34 is substantially annular and has anumber of flaps 36 on its interior surface which will interlock withridges 37 on the mouthpiece 5 a of the inhaler. The flaps 36 areorientated such that the mouthpiece 5 a will only be driven in onedirection of rotation with the gripping part 5 c.

[0096] Preferably, the mouthpiece 5 a is rotated at the same time assubstance is released into the dosing unit of the inhaler 5, i.e. byrotating the base 1 of the inhalation device in direction R1 in FIG. 15when the body 2 has been lifted to the extended position. Afterinhalation of the substance, the base 1 will then be rotated back indirection R2 but the flaps 35 will simply slip over the ridges 37 whichis necessary since the mouthpiece 5 a can rotate only in direction R1with respect to the body portion 5 b. Thus, the rotation of themouthpiece 5 a will result in cleaning of the interior surfaces of theinhaler 5 (for details of operation of the inhaler reference should bemade to WO98/41256) only when the base 1 is rotated in direction R1.

[0097] The inhaler 5 has main inlets 38 just above the gripping part 5 cand a number of bypass inlets 39 just below the mouthpiece 5 a throughwhich air can flow into the inhaler 5 to lift the substance to beinhaled from the dosing unit (not visible) within the body portion 5 b.

[0098] A sealing ring 40 between the mouthpiece 5 a and the mouthpieceseal support 29 prevents air from leaking into the dispersion chamber 18rather than passing into the inhaler 5.

[0099] Preferably, the inhalation device includes a stop element 41which is configured to ensure that only inhalers with a certainmouthpiece design can be inserted into the inhalation device. Should theinhalation device be required for use with inhalers having a large rangeof different mouthpieces the stop element 41 could be omitted. The stopelement 41 will typically have an identical internal configuration tothe mouthpiece of the inhaler which is to be inserted into theinhalation device and will rotate with the mouthpiece.

[0100] The dispersion chamber 18 lies within a disposable inner sleeve42. For details of the disposable inner sleeve 42, reference should nowbe made to FIGS. 34 and 35. The disposable inner sleeve 42 comprises asubstantially cylindrical body 45 with a plurality of holes 43 in aflanged rim 44 located at one end of the body.

[0101] The disposable inner sleeve 42 is connected to a disposable innercap 46, and a disposable outer cap 47. Between the inner cap 46 andouter cap 47 is a desiccant disc 48 for drying the air within theinhalation device. It is intended that the sleeve 42 and caps 46, 47 aredisposable because after repeated use of the inhalation device,particles of the substance being inhaled will collect on the interiorsurfaces of these elements which will eventually hamper the performanceof the inhalation device.

[0102] The mouthpiece 17 of the inhalation device slots into thedisposable outer cap 47 and can also be disposed of if necessary.

[0103] The disposable inner sleeve 42 slots into an inner piston sleeve49 which can slide on the inner sleeve 22. For details of the innerpiston sleeve 49 reference should be made to FIGS. 36 and 37. The innerpiston sleeve 49 comprises a cylindrical body 50, having a flanged rim51 with a plurality of holes 52 at one end. The other end of thecylindrical body 50 includes an inner rim 53 which bears on the outersurface of inner sleeve 22.

[0104] There is an inner seal 54 which sits against the rim 53 insidethe inner piston sleeve 49. Below the inner seal 54 is a latch supportring 55. For details of the latch support ring 55 reference should bemade to FIGS. 38 and 39. The latch support ring 52 comprises a lip 56with a slot 57 therethrough.

[0105] A piston 58 is located adjacent to the latch support ring 55 andis moveable with the inner piston sleeve 49. For details of the piston58 reference should now be made to FIGS. 40 and 41. The piston 58 has asubstantially cylindrical body 59 with a latch 60. The latch 60 is inthe form of a leg with a flange 61. The piston 58 also comprises anannular flange 62 in which a piston seal 63 sits. Reference should nowbe made to FIGS. 42, 43 and 44 for details of the piston seal 63. Thepiston seal 63 is constructed from an outer ring 63 a and an inner ring63 b. Preferably, the inner ring 63 b forms the leading edge of the sealwhen the piston 58 fires (see FIGS. 21 and 22) and the outer ring 63 aforms the trailing edge. The piston seal 63 should be manufactured tosuit the sliding motion of the piston 58, i.e. not too tight sincemovement will be affected and not too loose otherwise there will bedecreased suction in the suction chamber 19 if the seal leaks.

[0106] For manufacturing purposes, the outer ring 63 a and inner ring 63b can be connected by spaced thin connecting bridges or strips tofacilitate injection moulding of the parts.

[0107] In the retracted position of the body 2, the piston 58 sitsadjacent to the latch support ring 55 with the flange 61 on latch 60resting against the lip 56 on the latch support ring 55. When the body 2is lifted to the extended position shown in FIG. 16, the piston 58 andlatch support ring 55 move with the inner sleeve 42 and inner pistonsleeve 49.

[0108] A transparent outer sleeve 64 which is fixed to the base 1cooperates with the piston 58. The piston 58 can slide with respect tothe outer sleeve 64 from the retracted position (FIGS. 12 and 13) to theextended position (FIGS. 15 and 16). Reference should now be made toFIGS. 45 and 46 which show details of the outer sleeve 64. The outersleeve 64 is substantially cylindrical but has a cam surface 65 on itsinner surface. The cam surface 65 cooperates with the outer surface ofpiston 58 when the piston is in the extended position in FIG. 16. Whenthe base 1 is rotated to prime the inhalation device for use (FIGS. 17,18 and 19 and FIGS. 20, 21 and 22) the cam surface 65 will eventuallypush the latch 60 through the hole 57 in the lip 56 on the latch supportring 55. At this point, the piston 58 will be forced downwardly throughthe latch support ring 55 by a spring 67 which sits between the innerpiston sleeve 49 and the piston 58. The volume of the suction chamber 19will increase on release of the piston 58 and draw air from thedispersion chamber 18 through the holes 43 and 52 in the inner sleeve 42and inner piston sleeve 49. A negative pressure will then be created inthe dispersion chamber 18.

[0109] The outer sleeve 64 has a number of air vents 66 which allow airto be drawn in from outside the inhalation device when the piston 58 isreleased and accordingly, an airflow is created through the inhaler 5 asa result of the negative pressure in the dispersion chamber 18.

[0110] A piston clamp ring 68 is located between the piston seal 63 andspring 67 which serves to clamp the piston seal 63 on the piston 58within the annular flange 62. Reference should now be made to FIGS. 47,48 and 49 for details of the profile of piston clamp ring 68.

[0111] The external sleeve 69 forms part of the external surface of thebody 2 of the inhalation device. Details of the external sleeve 69 canbe seen in FIG. 50. The external sleeve 69 has a threaded end 70 whichthreads into the outer cap 47. In this way, the disposable outer cap 47,disposable inner cap 46, disposable inner sleeve 42 and the desiccantdisc 48 can be removed and replaced. The external sleeve 69 slides overthe external surface of the outer sleeve 64.

[0112] The actuation of the inhalation device will now be described withreference to FIGS. 11 to 22.

[0113]FIGS. 11, 12 and 13 show various views of the inhalation devicewhen the body is in the retracted (or rest) position and an inhaler 5has been inserted through the base 1.

[0114] In FIGS. 14, 15 and 16, the body 2 has been lifted away from thebase 1 to the extended position. In FIGS. 15 and 16 it can be seen thatthe inhaler 5 (which is held by the base 1) remains stationary whilstthe disposable inner sleeve 42, the inner piston sleeve 49, the piston58 and the latch support ring 55 move upwards with the body 2. Thelifting of the body 2 reveals the air vents 66 in the outer sleeve 64which will allow air to flow into the inhalation device.

[0115] In FIGS. 17, 18 and 19, the base 1 has been rotated with respectto the body 2. In these Figures the inhalation device is shown justprior to the piston 58 being released. When the base 1 is rotated, thegripping part 5 c and mouthpiece 5 a of the inhaler 5 rotatesimultaneously. This is achieved as a result of the connection betweenthe mouthpiece drive support 24 and the mouthpiece drive 34 which linkthe gripping part 5 c and mouthpiece 5 a rotationally when the base 1 isrotated in direction R1. In this way, the interior surfaces of theinhaler 5 can be cleaned by the scraping elements actuated by therotation of the mouthpiece 5 a prior to each use. The inner sleeve 22does not rotate with the base 1 and, therefore, the body portion 5 b ofthe inhaler 5 is held by the gripping collar 23 whilst the gripping part5 c and mouthpiece 5 a rotate.

[0116] In FIGS. 20, 21 and 22 the piston 58 has been released drawingair into the inhalation device by the creation of a negative pressure inthe dispersion chamber 18. The piston 58 is held by the latch supportring 55 during rotation of the base 1 until the cam surface 65 on theinterior of the outer sleeve 64 makes contact with the latch 60 on thepiston. At this point the flange 61 is pushed inwardly and slips throughthe hole 57 in the lip 56 on the latch support ring 55. It can be seenfrom FIG. 46 that the base 1 can rotate by a predetermined angle withoutthe cam surface 65 contacting the latch 60, this angle being sufficientto prime the inhaler 5 for use to release the substance into a dosingunit ready for inhalation. When the piston 58 is released air will flowthrough the air vents 66, the air slots 30 and air holes 31 in the innersleeve 22 and pass into the main inlets 38 and by-pass inlets 39 in theinhaler 5. The airflow will lift the substance to be inhaled into thedispersion chamber 18 ready for inhalation.

[0117] When the user has inhaled, the base 1 should be rotated back indirection R2. This will cause the gripping part 5 c to rotate also andensure that the inhaler 5 is returned to a position ready for subsequentuse. The mouthpiece 5 a will not rotate in direction R2 with respect tothe body portion 5 b and this has been taken into account by provisionof the flaps 36 inside the mouthpiece drive 34 which will only engagethe mouthpiece 5 a in direction R1. After rotation in direction R2, thebody 2 should be pushed back down towards the base 1 which will resultin the latch 60 on the piston 58 passing back through the latch supportring 55 ready for subsequent actuation.

[0118] The cover 3 should be replaced after use to ensure that thecontents of the inhalation device are maintained as dry as possible. Adesiccant disc 48 is located in the cavity between the inner cap 46 andouter cap 47 which can be replaced when necessary. The drying agent cantake many forms but the desiccant disc 48 is very practical for thispurpose. In order to encourage the user to replace the cover 3, theouter surfaces of the cover 3 and base 1 can be decorated with anartwork comprising two parts which is only made complete by securing thecover 3 in position over the base 1. Alternatively, an audible alarm canbe located on the base 1 of the inhalation device which is actuatedafter a delay period which is sufficient to allow the user to actuatethe inhalation device.

[0119] Whilst the preferred embodiment of the inhalation device includesthe stop element 41 to ensure that the inhalation device works only withcertain inhalers, the stop element 41 could be omitted allowing use withany inhaler having the same configuration of gripping part 5 c.Furthermore, the mouthpiece drive support 24 and mouthpiece drive 34could be omitted should the inhalation device be required for use withan inhaler which has a rotatable gripping part 5 c but the mouthpiece 5a does not need to be rotated.

[0120] The inhalation device described and depicted herein hassignificant advantages over prior art devices by virtue of its compactdesign, increased performance characteristics and the fact that it isable to work with inhalers which incorporate an internal scrapingelement.

1. An inhalation device for use with an inhaler comprising a dispersionchamber constructed for fluid communication with the inhaler, a suctionchamber in fluid communication with the dispersion chamber, the suctionchamber being constructed to enable the internal volume of said suctionchamber to be increased during use which produces a negative pressure insaid dispersion chamber thereby drawing a substance to be inhaled fromthe inhaler into the dispersion chamber for subsequent inhalationwherein, in use, the dispersion chamber is mounted telescopically aroundthe inhaler.
 2. An inhalation device as claimed in claim 1, wherein apiston is moveable within the suction chamber.
 3. An inhalation deviceas claimed in claim 2, wherein the piston has an annular construction.4. An inhalation device as claimed in claim 3, wherein the pistoncarries an annular seal member.
 5. An inhalation device as claimed inclaim 4, wherein the annular seal member comprises inner and outercoaxial annular seals.
 6. An inhalation device as claimed in anypreceding claim, further comprising a filter between the dispersionchamber and suction chamber to prevent the dispersed substance fromentering the suction chamber.
 7. An inhalation device as claimed in anyof claims 2 to 6, wherein the dispersion chamber is mountedtelescopically within the suction chamber.
 8. An inhalation device asclaimed in claim 7, wherein the piston is releasably connected adjacentto and moveable with the dispersion chamber which is moveable between aretracted position, where it surrounds the inhaler, to an extendedposition, where it sits substantially above the inhaler.
 9. Aninhalation device as claimed in claim 8, wherein the device furthercomprises a releasing mechanism for releasing the piston from thedispersion chamber and a biasing means for biasing the piston away fromthe dispersion chamber when in the extended position and the device isprimed for use.
 10. An inhalation device as claimed in claim 9, whereinwhen the piston is released the movement of the piston within thesuction chamber creates a negative pressure in the dispersion chamberthereby drawing air through the inhaler.
 11. An inhalation device asclaimed in any preceding claim, wherein the inhalation device comprisesa base and a body and is primed for use by lifting the body away fromthe base and then rotating the base with respect to the body.
 12. Aninhalation device as claimed in claim 11, wherein the dispersion chamberis located in the body and the inhaler is held in the base.
 13. Aninhalation device as claimed in claim 12, wherein the inhaler has amouthpiece, a body portion and a rotatable gripping part.
 14. Aninhalation device as claimed in claim 13, wherein when the inhaler islocated within the inhalation device, the rotatable gripping part isheld in the base of the inhalation device so that the rotation of thebase causes rotation of the rotatable gripping part.
 15. An inhalationdevice as claimed in claim 14, wherein the rotation of the gripping partof the inhaler causes the substance to move into a release positionwithin the body portion of the inhaler.
 16. An inhalation device asclaimed in any of claims 13 to 15, wherein the inhaler mouthpiece isrotatable having a scraping means acting on its interior surfaces whichcleans the inhaler prior to each use.
 17. An inhalation device asclaimed in claim 16, wherein the inhalation device further comprises aconnecting means which links the rotational movement of the grippingpart of the inhaler to the rotational movement of the mouthpiece of theinhaler such that rotation of the base in one direction results in thecleaning of the interior surfaces of the inhaler
 18. An inhalationdevice as claimed in any of claims 13 to 17, wherein the inhalationdevice further comprises a clamping means which holds the body portionof the inhaler whilst allowing the gripping part to rotate with thebase.
 19. An inhalation device as claimed in any of claims 11 to 18,wherein the body of the inhalation device further comprises a means fordrying the air contained within the device and the substance to beinhaled.
 20. An inhalation device as claimed in any of claims 11 to 19,wherein the body of the inhalation device further comprises a number ofseparable elements which can be replaced after a predetermined number ofuses.
 21. An inhalation device as claimed in any preceding claim,wherein the inhalation device comprises a stop element which isconfigured to ensure that only certain inhalers can be inserted into thedevice.
 22. An inhalation device as claimed in any preceding claim,further comprising a cover which at least partially encases theinhalation device when not in use.
 23. An inhalation device as claimedin claim 22, wherein the cover seals and encases the body of the deviceand connects with the base of the device.
 24. An inhalation device asclaimed in claim 23, wherein the cover and base include parts of anartwork which is only made complete when the user has replaced the coveron the base thereby ensuring that the contents of the inhalation deviceare sealed within.
 25. An inhalation device as claimed in any of claims22 to 24, wherein the inhalation device comprises an audible alarm whichis activated after a given period of time should the cover not bereplaced.
 26. An inhalation device for use with an inhaler substantiallyas herein described with reference to the accompanying drawings.